Question: Simplify the expression. $(5x+3)(-x-3)$
Explanation: First distribute the ${5x+3}$ onto the ${-x}$ and ${-3}$ $ = {-x}({5x+3}) + {-3}({5x+3})$ Then distribute the ${-x}.$ $ = ({-x} \times {5x}) + ({-x} \times {3}) + {-3}({5x+3})$ $ = -5x^{2} - 3x + {-3}({5x+3})$ Then distribute the ${-3}$ $ = -5x^{2} - 3x + ({-3} \times {5x}) + ({-3} \times {3})$ $ = -5x^{2} - 3x - 15x - 9$ Finally, combine the $x$ terms. $ = -5x^{2} - 18x - 9$